Magnetic nanoparticles as efficient bulk pinning centers in type-II superconductors

TL;DR

This paper investigates how magnetic nanoparticles can significantly improve flux pinning in type-II superconductors, combining theoretical calculations and experimental validation to demonstrate enhanced vortex pinning with magnetic inclusions.

Contribution

It introduces a combined theoretical and experimental approach to show that magnetic nanoparticles enhance flux pinning in type-II superconductors, which was not previously demonstrated.

Findings

Magnetic nanoparticles increase vortex pinning efficiency.

Experimental results show improved critical current in MgB2 with magnetic inclusions.

Magnetic pinning centers outperform nonmagnetic ones in flux pinning.

Abstract

Enhancement of flux pinning by magnetic nanoparticles embedded into the bulk of type-2 superconductor is studied both theoretically and experimentally. Magnetic part of the pinning force associated with the interaction between a spherical magnetic inclusion and an Abrikosov vortex was calculated in the London approximation. Calculations are supported by the experimental results obtained on sonochemically modified MgB2 superconductor with embedded magnetic Fe2O3 nanoparticles and compared to MgB2 with nonmagnetic Mo2O5 pinning centers of similar concentration and particle size distribution. It is shown that ferromagnetic nanoparticles result in a considerable enhancement of vortex pinning in large-kappa type-2 superconductors.